EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1249 AM EDT WED APR 01 2015 VALID 12Z SAT APR 04 2015 - 12Z WED APR 08 2015 ...OVERVIEW... UPPER PATTERN NEXT WEEK WILL TREND TOWARD MORE RIDGING IN THE EASTERN CONUS AS TROUGHING PUSHES THROUGH THE WEST. EXITING SYSTEM IN THE EAST WILL USHER IN COOLER AIR YET AGAIN TO THE NORTHEAST THIS WEEKEND AS A NORTHERN STREAM STATIONARY BOUNDARY SETTLES OVER THE REGION. ALONG THIS FRONT WILL BE THE GREATEST UNCERTAINTY IN SFC TEMPERATURES. BACK TO THE WEST... INCOMING TROUGHING WILL SUPPORT A SFC COLD FRONT THAT WILL MARCH THROUGH THE ROCKIES AND ONTO THE PLAINS NEXT WEEK. ...GUIDANCE PREFERENCES AND SENSIBLE WEATHER HIGHLIGHTS... ENSEMBLES HAVE BEEN THE SAVING GRACE IN THIS FORECAST... PARTICULARLY OUT WEST... WHERE THE ECMWF AND GFS SEEM TO HAVE EXHIBITED THEIR BIASES -- ECMWF TOO SLOW AND GFS TOO QUICK. THE COMPROMISE BETWEEN THE ENSEMBLE SYSTEMS HAS SERVED WELL AND THIS CONTINUES TO BE THE PREFERRED BEST TRACK. 12Z GFS/ECMWF TIED IN NICELY WITH THE 12Z NAEFS/ECENS MEANS THROUGH THE PERIOD AND THAT BLEND WAS CARRIED THROUGH TO NEXT WED. 12Z ECMWF LIED ON THE QUICKER SIDE WITH THE FLOW PATTERN BY THE END OF THE PERIOD AND THE 18Z GFS TRENDED BACK TO A MUCH SLOWER WESTERN UPPER LOW -- WHICH DOES NOT FIT THE TREND IN THE GUIDANCE OVER THE PAST 36 HRS -- BUT WITH CONTINUED HIGH SPREAD UPSTREAM NEITHER CANNOT TOTALLY BE RULED OUT. TEMPERATURE EXTREMES MAY BE LIMITED DURING THE PERIOD... WITH MAINE BEING HIGHLIGHTED AS A POTENTIAL COLD SPOT ON MONDAY. RECORD LOW MINS AND MAXES MAY BE CHALLENGED AND HAVE BEEN CONSISTENTLY SHOWING UP IN THE FORECAST GUIDANCE. OTHERWISE... RETURN FLOW OUT OF THE GULF WILL INCREASE THE RAIN THREAT FOR THE OH/TN/MS VALLEYS TUE-WED WHILE IN THE PAC NW ONLY MODEST RAINS ARE EXPECTED. FRACASSO